coating hardness using Hipojet 2700M air cooled

[JRB VIRANI]

Dear HVOF expert,
i am getting coating hardness almost nearer to 700-800 HV0.3 against requirement of 1100 HV0.3 .
we are using HIPOJET 2700 air cooled coating system and our fuel gas is LPG .
as usual coating machine supplier raise his hand by saying that hipojet system can not provide 1100 HV ,purchase other new model from us . our powder is WC-10Co-4Cr.

is there any expert advise to achieve required hardness (minimum 1100 HV0.3) ???
thanks in advance [/size][/font]

[Vadim Verlotski]

Dear HVOF expert,
i am getting coating hardness almost nearer to 700-800 HV0.3 against requirement of 1100 HV0.3 .
we are using HIPOJET 2700 air cooled coating system and our fuel gas is LPG .
as usual coating machine supplier raise his hand by saying that hipojet system can not provide 1100 HV ,purchase other new model from us . our powder is WC-10Co-4Cr.

is there any expert advise to achieve required hardness (minimum 1100 HV0.3) ???
thanks in advance [/size][/font]

Hi,
Your coating machine supplier said truth this time. With your air-cooled HIPOJET 2700 you can not reach the necessary speeds for ordinary (22-45 microns) WC-Co-Cr powder. The only thing you can try with this burners is to spray the fine-grained (<22 microns) WC-Co-Cr powder, but even in this case, reaching > 1000 HV is very difficult for your slow burner.

[JRB VIRANI]

Dear HVOF expert,
i am getting coating hardness almost nearer to 700-800 HV0.3 against requirement of 1100 HV0.3 .
we are using HIPOJET 2700 air cooled coating system and our fuel gas is LPG .
as usual coating machine supplier raise his hand by saying that hipojet system can not provide 1100 HV ,purchase other new model from us . our powder is WC-10Co-4Cr.

is there any expert advise to achieve required hardness (minimum 1100 HV0.3) ???
thanks in advance [/size][/font]

Hi,
Your coating machine supplier said truth this time. With your air-cooled HIPOJET 2700 you can not reach the necessary speeds for ordinary (22-45 microns) WC-Co-Cr powder. The only thing you can try with this burners is to spray the fine-grained (<22 microns) WC-Co-Cr powder, but even in this case, reaching > 1000 HV is very difficult for your slow burner.

Dear Vadim,
can we increase hardness by converting Hipojet 2700 air cooled gun to Water cooled sytem ???there is one option available to convert it from air cooled to water cooled.
I mean can we increase hardness by installing water jam box ,chiller and water cooling jackets at gun front with water in & out. we are currently using coating powder having grain size 15-45 micron .

[Vadim Verlotski]

Dear HVOF expert,
i am getting coating hardness almost nearer to 700-800 HV0.3 against requirement of 1100 HV0.3 .
we are using HIPOJET 2700 air cooled coating system and our fuel gas is LPG .
as usual coating machine supplier raise his hand by saying that hipojet system can not provide 1100 HV ,purchase other new model from us . our powder is WC-10Co-4Cr.

is there any expert advise to achieve required hardness (minimum 1100 HV0.3) ???
thanks in advance [/size][/font]

Hi,
Your coating machine supplier said truth this time. With your air-cooled HIPOJET 2700 you can not reach the necessary speeds for ordinary (22-45 microns) WC-Co-Cr powder. The only thing you can try with this burners is to spray the fine-grained (<22 microns) WC-Co-Cr powder, but even in this case, reaching > 1000 HV is very difficult for your slow burner.

Dear Vadim,
can we increase hardness by converting Hipojet 2700 air cooled gun to Water cooled sytem ???there is one option available to convert it from air cooled to water cooled.

Yes, the water-cooled system has higher speed than air-cooled, and you can slightly improve the coating hardness. But I am not sure that it is enough for > 1100 HV. It's best to do both: water-cooled Hipojet 2700 plus fine-grained powder.

[JRB VIRANI]

Dear HVOF expert,
i am getting coating hardness almost nearer to 700-800 HV0.3 against requirement of 1100 HV0.3 .
we are using HIPOJET 2700 air cooled coating system and our fuel gas is LPG .
as usual coating machine supplier raise his hand by saying that hipojet system can not provide 1100 HV ,purchase other new model from us . our powder is WC-10Co-4Cr.

is there any expert advise to achieve required hardness (minimum 1100 HV0.3) ???
thanks in advance [/size][/font]

Hi,
Your coating machine supplier said truth this time. With your air-cooled HIPOJET 2700 you can not reach the necessary speeds for ordinary (22-45 microns) WC-Co-Cr powder. The only thing you can try with this burners is to spray the fine-grained (<22 microns) WC-Co-Cr powder, but even in this case, reaching > 1000 HV is very difficult for your slow burner.

Dear Vadim,
can we increase hardness by converting Hipojet 2700 air cooled gun to Water cooled system ???there is one option available to convert it from air cooled to water cooled.

Yes, the water-cooled system has higher speed than air-cooled, and you can slightly improve the coating hardness. But I am not sure that it is enough for > 1100 HV. It's best to do both: water-cooled Hipojet 2700 plus fine-grained powder.

Thanks vadim,
for sharing your view & technical expertise on this topic.
i hope porosity level will also down by replacing air cooled to water cooled . by using water cooled system , i hope we need less grinding tolerance compare to air cooled system ... correct me if i am wrong

[Vadim Verlotski]

Dear HVOF expert,
i am getting coating hardness almost nearer to 700-800 HV0.3 against requirement of 1100 HV0.3 .
we are using HIPOJET 2700 air cooled coating system and our fuel gas is LPG .
as usual coating machine supplier raise his hand by saying that hipojet system can not provide 1100 HV ,purchase other new model from us . our powder is WC-10Co-4Cr.

is there any expert advise to achieve required hardness (minimum 1100 HV0.3) ???
thanks in advance [/size][/font]

Hi,
Your coating machine supplier said truth this time. With your air-cooled HIPOJET 2700 you can not reach the necessary speeds for ordinary (22-45 microns) WC-Co-Cr powder. The only thing you can try with this burners is to spray the fine-grained (<22 microns) WC-Co-Cr powder, but even in this case, reaching > 1000 HV is very difficult for your slow burner.

Dear Vadim,
can we increase hardness by converting Hipojet 2700 air cooled gun to Water cooled system ???there is one option available to convert it from air cooled to water cooled.

Yes, the water-cooled system has higher speed than air-cooled, and you can slightly improve the coating hardness. But I am not sure that it is enough for > 1100 HV. It's best to do both: water-cooled Hipojet 2700 plus fine-grained powder.

Thanks vadim,
for sharing your view & technical expertise on this topic.
i hope porosity level will also down by replacing air cooled to water cooled . by using water cooled system , i hope we need less grinding tolerance compare to air cooled system ... correct me if i am wrong

You're right. Hardness of WC-Co-Cr coating is the function of its porosity: the smaller the porosity the harder and less rough is this coating. A hardness of 1100 HV corresponds to the porosity of about 0.5% and minimum particle velocity of over 600 m/s.
In order to produce maximum gas speed with your burner you need a high pressure in the combustion chamber. By the way, your gas (LPG) is not the most powerful. More power (higher gas temperature and gas speed) you get with ethene.

[JRB VIRANI]

Hi,
Your coating machine supplier said truth this time. With your air-cooled HIPOJET 2700 you can not reach the necessary speeds for ordinary (22-45 microns) WC-Co-Cr powder. The only thing you can try with this burners is to spray the fine-grained (<22 microns) WC-Co-Cr powder, but even in this case, reaching > 1000 HV is very difficult for your slow burner.

Dear Vadim,
can we increase hardness by converting Hipojet 2700 air cooled gun to Water cooled system ???there is one option available to convert it from air cooled to water cooled.

Yes, the water-cooled system has higher speed than air-cooled, and you can slightly improve the coating hardness. But I am not sure that it is enough for > 1100 HV. It's best to do both: water-cooled Hipojet 2700 plus fine-grained powder.

Thanks vadim,
for sharing your view & technical expertise on this topic.
i hope porosity level will also down by replacing air cooled to water cooled . by using water cooled system , i hope we need less grinding tolerance compare to air cooled system ... correct me if i am wrong

You're right. Hardness of WC-Co-Cr coating is the function of its porosity: the smaller the porosity the harder and less rough is this coating. A hardness of 1100 HV corresponds to the porosity of about 0.5% and minimum particle velocity of over 600 m/s.
In order to produce maximum gas speed with your burner you need a high pressure in the combustion chamber. By the way, your gas (LPG) is not the most powerful. More power (higher gas temperature and gas speed) you get with ethene.

Thanks ,
let me try with new fuel,new powder particle size and new hybrid coating gun.
will share result after this trial.

[JRB VIRANI]

Hi,
Your coating machine supplier said truth this time. With your air-cooled HIPOJET 2700 you can not reach the necessary speeds for ordinary (22-45 microns) WC-Co-Cr powder. The only thing you can try with this burners is to spray the fine-grained (<22 microns) WC-Co-Cr powder, but even in this case, reaching > 1000 HV is very difficult for your slow burner.

Dear Vadim,
can we increase hardness by converting Hipojet 2700 air cooled gun to Water cooled system ???there is one option available to convert it from air cooled to water cooled.

Yes, the water-cooled system has higher speed than air-cooled, and you can slightly improve the coating hardness. But I am not sure that it is enough for > 1100 HV. It's best to do both: water-cooled Hipojet 2700 plus fine-grained powder.

Thanks vadim,
for sharing your view & technical expertise on this topic.
i hope porosity level will also down by replacing air cooled to water cooled . by using water cooled system , i hope we need less grinding tolerance compare to air cooled system ... correct me if i am wrong

You're right. Hardness of WC-Co-Cr coating is the function of its porosity: the smaller the porosity the harder and less rough is this coating. A hardness of 1100 HV corresponds to the porosity of about 0.5% and minimum particle velocity of over 600 m/s.
In order to produce maximum gas speed with your burner you need a high pressure in the combustion chamber. By the way, your gas (LPG) is not the most powerful. More power (higher gas temperature and gas speed) you get with ethene.

Dear Vadim,
i have 2 option in fine size powder one is agglomereted and sintered grade (more spherical shape)
second is sintered and crushed grade (irregular shape) .....which one is more suitable in this typical case....????

[Vadim Verlotski]

Dear Vadim,
can we increase hardness by converting Hipojet 2700 air cooled gun to Water cooled system ???there is one option available to convert it from air cooled to water cooled.

Yes, the water-cooled system has higher speed than air-cooled, and you can slightly improve the coating hardness. But I am not sure that it is enough for > 1100 HV. It's best to do both: water-cooled Hipojet 2700 plus fine-grained powder.

Thanks vadim,
for sharing your view & technical expertise on this topic.
i hope porosity level will also down by replacing air cooled to water cooled . by using water cooled system , i hope we need less grinding tolerance compare to air cooled system ... correct me if i am wrong

You're right. Hardness of WC-Co-Cr coating is the function of its porosity: the smaller the porosity the harder and less rough is this coating. A hardness of 1100 HV corresponds to the porosity of about 0.5% and minimum particle velocity of over 600 m/s.
In order to produce maximum gas speed with your burner you need a high pressure in the combustion chamber. By the way, your gas (LPG) is not the most powerful. More power (higher gas temperature and gas speed) you get with ethene.

Dear Vadim,
i have 2 option in fine size powder one is agglomereted and sintered grade (more spherical shape)
second is sintered and crushed grade (irregular shape) .....which one is more suitable in this typical case....????

Hi,
agglomereted and sintered powder is always better than sintered and crushed. If the two powders have the same grain size, take an agglomerated sintered one.

[Met.Eng.]

Hipojet gun use Low pressure powder feeder(hopper). Gun back pressure is 3.9 bar for hybrid and air cooled gun. There is no big difference between air and water cooled gun for Mec Hipojet 2700. Also the flame velocity for hybrid is higher than air cooled gun but the result is nearly same. Yes if u use hybrid gun you get a bit lower surface roughness and denser coating. But DJ 2700 has a different nozzle and powder injection design . DJ 2700 air cooled gun use 6 bar hopper like hipojet air and hybrid gun. But DJ 2700 hybrid gun must use 12 bar high pressure hopper. And their gun back pressure 6.9 bar. Thats the reason coating quality between two types of gun. So I think if you think of an improvement your coating quality , you should change the gun and the hopper.

[Stephen Booth]

Hipojet gun use Low pressure powder feeder(hopper). Gun back pressure is 3.9 bar for hybrid and air cooled gun. There is no big difference between air and water cooled gun for Mec Hipojet 2700. Also the flame velocity for hybrid is higher than air cooled gun but the result is nearly same. Yes if u use hybrid gun you get a bit lower surface roughness and denser coating. But DJ 2700 has a different nozzle and powder injection design . DJ 2700 air cooled gun use 6 bar hopper like hipojet air and hybrid gun. But DJ 2700 hybrid gun must use 12 bar high pressure hopper. And their gun back pressure 6.9 bar. Thats the reason coating quality between two types of gun. So I think if you think of an improvement your coating quality , you should change the gun and the hopper.

agreed